Cyclic imines as biocides in petroleum products

ABSTRACT

A method of preventing growth of micro-organisms in petroleum hydrocarbons in contact with water by incorporating from about 0.005 to 0.1 percent by volume of a cyclic imine selected from the class comprising pyrrolidine, piperidine and hexamethylene imine into said petroleum hydrocarbon.

United States Patent George W. Eekert;

Raymond Cadorette, both of Wnppingers Falls, N.Y.

Dec. 19, 1968 Dec. 2 l 1971 Texaco Inc.

New York, N.Y.

inventors Appl. No. Filed Patented Assignee CYCLIC lMlNES AS BIOCIDES IN PETROLEUM PRODUCTS 1 Claim, No Drawings US. Cl 44/63, 210/64 Int. Cl C101 1/14 Field of Search 44/63;

Primary ExaminerDaniel E. Wyman Assistant Examiner-C. F. Dees Attorneys-K. E. Kavanagh and Thomas H. Whaley ABSTRACT: A method of preventing growth of micro-organisms in petroleum hydrocarbons in contact with water by incorporating from about 0.005 to 0.1 percent by volume of a cyclic imine selected from the class comprising pyrrolidine, piperidine and hexamethylene imine into said petroleum hydrocarbon.

CYCLIC lMlNES AS BIQCIDES IN PETROLEUM PRODUCTS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the preservation of petroleum products and like substances in storage, and more particularly to the inhibition of the action of micro-organisms on petroleum and other materials subject to metabolism by micro-organisms present in the water layer in vessels and in storage tanks.

2. Description of the Prior Art in petroleum product storage and handling facilities, such as storage tanks, pipelines, fuel lines and other equipment, petroleum products often may be in contact with water containing micro-organisms. This is particularly true in the case in oil storage tanks where a 'water layer usually is provided in the bottom of the tank to insure against loss by leakage, the water being replenished as necessary. Micro-organisms such as bacteria, yeast, molds, actinomyces, etc., generally are present in such tank bottom water, the organisms usually being of a type which functions most efiectively at the interface between the stored material and water to metabolize the hydrocarbons or constituents thereof. This metabolism not only results in loss of petroleum material but in the case of refined products it is also undesirable in other respects in that it commonly causes of the cyclic imines of this invention, namely pyrrolidine,

discoloration of the product, formation of hydrogen sulfide it and undesirable gummy substances, formation of peroxides which effect the oxidation susceptibility of the petroleum product, and formation of many other undesirable compounds, such as acids. Discoloration in the case of light colored petroleum products is highly undesirable and in some cases, as with so-called white distillates or kerosene fractions, the discoloration can be so severe as to require re-refining of the product. Where additives are present in the petroleum, as is usually the case with gasoline and lubricating oils, the formation of gummy substances mayrepresent loss of suchadditives or undesirable conversion thereof. Obviously, such microbial activity also is harmful to the tank structure as well since such tanks usually are formed of metal.

In the prior art it is known to inhibit the growth of micro-organisms present in water in contact with petroleum products by means of a biocide, usually added to the water phase. Although such water phase biocides are available and have been used for controlling the growth of micro-organisms in storage tanks, their use is not feasible under conditions where access to the water phase is impractical, as in wing tanks of airplanes and in fuel lines. In such situations a hydrocarbon phase biocide is desirable. However, it is important that any such materials added to a petroleum fraction or product should not adversely affect its properties. This is particularly essential when the petroleum material is a refined or finished product.

SUMMARY The present invention is directed to inhibiting the growth of micro-organisms in water which is in contact with petroleum material, especially refined petroleum products, by the addition of certain cyclic imines in small amounts to the petroleum material. Cyclic imines which are useful as biocides in accordance with this invention are pyrrolidine. piperidine and hexamethylene imine. these cyclic imines are characterized by possessing a ring structure consisting of from four to six methylene groups and one imine group. The cyclic imines of 6 T A-1 No additive centimeter volume of tap water was inoculated with a very small portion of growth scraped lightly from a blood agar culture of typical water bottoms microorganisms. The water as then overlain in a l-ounce bottle with 20 cc. of hydrocarbon material containing the biocide under test. The bottle was stoppered and allowed to remain at room temperature for 5 days with daily agitation. At the end of the 5 days, a loopful (about one small drop) of the water phase was streaked over a blood agar plate which was then left at room temperature for a period of 5 days or until a growth occurred, whichever came first. The effectiveness of the biocide was judged on the basis of whether there was or was not growth on the blood agar plate at the end of the 5-day period.

The results obtained with the cyclic imine biocides of this invention when added to gasoline, kerosene, jet fuel, furnace g i lan d diesel fuel are shown in table I.

The results presented in table I show that the addition of a very small amount (0.005 percent to 0.10 percent by volume) piperidine and hexamethylene imine, to a petroleum fuel prevents the growth of micro-organisms in water is in contact 0.005% hexamethylene imine. 0.01% hexamethylene imine... 0.10% hexamethylene imine 0.005% piperidine...

No growth No growth No growth.

No growth 0.01% piperidine. No growth 0.005% pyrrolidine................ No growth.

Kerosene No additive Profuse growth 0.005% hexamethylene imine. 0.01% hexamethylene imin 0.10% hexamethylene imin 0.005%piperidine... 0.01% piperidine. 0.005% pyrrolidine.

0.01% pyrrolidine .12! fuel No additive 0.01% hexamethylene imine.. 0.005% piperidine 0.01% piperidine... 0.005% pyrrolidine. 0.01% pyrrolidine N0. Zfurnace ail No additive 0.005% hexamethylene imine 0.01% hexamethylene imine..

n No growth.

Profuse growth. No growth. No growth. No growth. No growth. No growth. No growth. No growth. No growth.

0.01% pyrrolidine.. 0.05% pyrrolidine..

Accelerated rusting tests were conducted on selected test samples with the five types of petroleum fuels shown in table 1. 1n this accelerated test a specimen coupon of cold-rolled steel was immersed in a cc. sample of the test sample and 20 cc. of water for a period of 24 hours at room temperature. In every instance the percentage of the surface of specimen coupon covered by visible rust was less when the test sample contained a cyclic imine of this invention than when the imine was absent. Typical results of the accelerated rusting test are given in table 2 with the test sample identification referring to the compositions shown in table 1 got the same test identification number.

' sto ed fuel. v M

TABLE I Extent of growth of v microorganisms in Test Composition. by volume culture test Gasoline Profuse growth.

Diesel fuel E-l No additive Profuse growth. E-Z. 0 005% pyrrolidi V. sl. growth. E-3 0.01% pyrrolidine.. No growth.

TABLE ll wwmcu UUUU The: presence of the cyclic imines of this invention in the petroleum materials listed in table I was also investigated for possible adverse effects on other properties. Gasoline mixtures were tested with respect to Octane Numbers (Research and lvlotormethods). Copper corrosion (ASTM D-l), gum

(ASTM D-381 and oxidation stability (ASTM D52525). None of these properties of the gasoline were affected to any significant extent. Jet fuel mixtures were evaluated for possible effects on Luminometer Number, Water Separometer Inden, copper corrosion (ASTM D-)30) and existent gum (ASTM D38l58T). Furnace and diesel oil mixtures were tested for possible effects on potential deposit (ASTM D--2274), copper corrosion (ASTM D430) and pour point. The jet fuel, furnace oil, and diesel oil were not significantly affected with respect to any of these properties by the presence of the cyclic imines of the invention.

Obviously many modifications and variations of the invention as hereinabove set forth may be made without departing from the spirit and scope thereof and only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A method of inhibiting metabolism by microorganisms ofa liquid petroleum hydrocarbon fuel in contact with a water phase containing said microorganisms, said method comprising incorporating into said liquid petroleum hydrocarbon fuel a cyclic imine selected from the class consisting of pyrrolidine, piperidine and hexamethylene imine in an amount in the range of from about 0.005 percent to about 0.01 percent by volume to inhibit growth of microorganisms present in said water phase. 

